WASET
    Sukhwinder Singh Billing and  Sushma Gupta and  Sukhjit Singh Dhaliwal,  A Sandwich-type Theorem with Applications to Univalent Functions.   journal   = {International Journal of Mathematical and Computational Sciences}, [online]. World Academy of Science, Engineering and Technology.
    September 2009, vol. 33(9). 751 - 756
    [viewed 26 April 2024]. Available from: https://publications.waset.org/pdf/2210.